Module org.apache.lucene.sandbox
Package org.apache.lucene.sandbox.search

Class TermAutomatonQuery

java.lang.Object
org.apache.lucene.search.Query
org.apache.lucene.sandbox.search.TermAutomatonQuery
All Implemented Interfaces:
Accountable
public class TermAutomatonQuery extends Query implements Accountable
A proximity query that lets you express an automaton, whose transitions are terms, to match documents. This is a generalization of other proximity queries like PhraseQuery, MultiPhraseQuery and SpanNearQuery. It is likely slow, since it visits any document having any of the terms (i.e. it acts like a disjunction, not a conjunction like PhraseQuery), and then it must merge-sort all positions within each document to test whether/how many times the automaton matches.

After creating the query, use createState(), setAccept(int, boolean), addTransition(int, int, java.lang.String) and addAnyTransition(int, int) to build up the automaton. Once you are done, call finish() and then execute the query.

This code is very new and likely has exciting bugs!

  • Field Details

  • Constructor Details

    • TermAutomatonQuery

      public TermAutomatonQuery(String field)

  • Method Details

    • createState

      public int createState()
      Returns a new state; state 0 is always the initial state.

    • setAccept

      public void setAccept(int state, boolean accept)
      Marks the specified state as accept or not.

    • addTransition

      public void addTransition(int source, int dest, String term)
      Adds a transition to the automaton.

    • addTransition

      public void addTransition(int source, int dest, BytesRef term)
      Adds a transition to the automaton.

    • addAnyTransition

      public void addAnyTransition(int source, int dest)
      Adds a transition matching any term.

    • finish

      public void finish()
      Call this once you are done adding states/transitions.

    • finish

      public void finish(int determinizeWorkLimit)
      Call this once you are done adding states/transitions.
      Parameters:
      determinizeWorkLimit - Maximum effort to spend determinizing the automaton. Higher numbers allow this operation to consume more memory but allow more complex automatons. Use Operations.DEFAULT_DETERMINIZE_WORK_LIMIT as a decent default if you don't otherwise know what to specify.

    • createWeight

      public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException
      Description copied from class: Query
      Expert: Constructs an appropriate Weight implementation for this query.

      Only implemented by primitive queries, which re-write to themselves.

      Overrides:
      createWeight in class Query
      Parameters:
      scoreMode - How the produced scorers will be consumed.
      boost - The boost that is propagated by the parent queries.
      Throws:
      IOException

    • toString

      public String toString(String field)
      Description copied from class: Query
      Prints a query to a string, with field assumed to be the default field and omitted.
      Specified by:
      toString in class Query

    • getTermID

      private int getTermID(BytesRef term)

    • equals

      public boolean equals(Object other)
      Returns true iff o is equal to this.
      Specified by:
      equals in class Query
      See Also:

    • checkFinished

      private static boolean checkFinished(TermAutomatonQuery q)

    • equalsTo

      private boolean equalsTo(TermAutomatonQuery other)

    • hashCode

      public int hashCode()
      Description copied from class: Query
      Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.
      Specified by:
      hashCode in class Query
      See Also:

    • ramBytesUsed

      public long ramBytesUsed()
      Description copied from interface: Accountable
      Return the memory usage of this object in bytes. Negative values are illegal.
      Specified by:
      ramBytesUsed in interface Accountable

    • toDot

      public String toDot()
      Returns the dot (graphviz) representation of this automaton. This is extremely useful for visualizing the automaton.

    • rewrite

      public Query rewrite(IndexSearcher indexSearcher) throws IOException
      Description copied from class: Query
      Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

      Callers are expected to call rewrite multiple times if necessary, until the rewritten query is the same as the original query.

      The rewrite process may be able to make use of IndexSearcher's executor and be executed in parallel if the executor is provided.

      However, if any of the intermediary queries do not satisfy the new API, parallel rewrite is not possible for any subsequent sub-queries. To take advantage of this API, the entire query tree must override this method.

      Overrides:
      rewrite in class Query
      Throws:
      IOException
      See Also:

    • visit

      public void visit(QueryVisitor visitor)
      Description copied from class: Query
      Recurse through the query tree, visiting any child queries.
      Specified by:
      visit in class Query
      Parameters:
      visitor - a QueryVisitor to be called by each query in the tree